Method of hardening articles



Dec. 17, 1929. 'w. G. HILDoRF I METHOD OF HARDENING ARTICLES Filed Deo-5. 1927 2 sheets-shew l Dec. 17, 1929. w. G. HILDORF 1,740,347

" METHOD oF HARDENING ARTICLES Filed Dec. 5, 1927 2 Sheets-Sheet 2 359% l, a f,

UN I l E` STATES? WALTER. G. HILDORF, OF LANSING, MICHIGAN, PISSIGNOR IO REO IMIO'IOIHCAR COM PAT-ENT( OFFICE-,1,

PANY, F LANSING, MICHIGAN, A CORPORATION OF MICHIGAN METHODMOF. HARDEN'ING ARTICLES Application filed December 5, 1927-.` `Se1a111\o. 237,972.

A further object of this invention isto` provide a quenching` apparatus havingmeans for initially directinga quenching fluid into Contact with one faceof thearticle to be quenched, while maintaining the other face ofv the article to be quenched, free fromcontact with the quenching fluid. l

fi still-further object of this invention is to provide a quenching apparatus having vmeans for compensating for variations in the heights of the articles to be quenched, so

that the apparatus will readilyadapt itself.

to a number of different articlesof various heights.

Another objectof this invention is to pro-4 vide a quenching apparatus having meansA for pieventiiig Contact of the quenching fluid with one portion of 'the article being qucnched,whereby this portion of .the article will retain its toughness andits ability to resist shocks.

Other objects and advantages of this in'- vention will become apparent asthe following description proceeds.

Broadly my method consists in clamping;` a portion of the article to be quenchedrbe tween two members whereby the/clamped portion of the article will be protected'from contact with the quenching fluid and in subseqiiently lowering the clamped article into a bath of quenching fluid whereby the Vunclamped portion of the article may be treated with the quenching fluid. My method further includes the step of so directing the flow of the quenching fluid that one face of that portion of the articleto be quenched will be treated with the quenching'fluidin advance of the other face. This stepis of particular importance since I have found when an attempt is made to simultaneously i the article.

quench both faces of the article, eXtreme/dif-A ficulty is experienced in that the ,quenching yis often uneven and the article is distorted 1 during:shrinkage This is particularly true where the article is flanged, since it is almost impossible to so control the `quenching fluid as to simultaneously and evenly eEect a con" tact ofthe quenching fluid with both faces of However, by: ydirecting the quenching fluid so that one face of the article is quenched in advance of the other andloy initially maintainingithe. quenching fluid free from contact with one face of the article, this dilliculty is eliminated and the article is not distorted upon shrinkage.4

My method .finds particular. utility in quenching brake drums formed of a steel ofal i high carbon content, this steel being rolled into sheets, `then heated and pressed into dinms'which are` subsequently quenched.` I will therefore proceed to describe my method in connection with the quenchingof a brake drum,.but:it is to bei clearly understood that.

the description will be for ,the purpose ofuillustrationonly, andthatithe features of the inventive idea may bey efliciently embodied 4 in the method of quenching or treating with a "fluid any` article regardless of itscharacter.

As brought out above, .inithe forming ofy the brake drum, the drum is preferably ,first rolled from a sheet. of steel of a highcarbon content. The drum is then heated and loosely mounted on anfexpansible yform which hasH been expanded to the desired diameter of theU finished drum i The web of the. drum is then 1 clamped between the upper portion ofthe `caused to firstcontact withitheinner periph` 4ery of the brake drumiand is prevented from initially contacting .with the .outer periphery of the drum. After the inner periphery of the drum has beentieated `by the quenching fluid, and the drum Vhas-been set thereby, the i quenching fluid is then permitted .to Contact with the outer .periphery'of the brake drum1 to completely quench the drum. As brought out before, durin@ this entire operation the web portion of the drum is maintained substantially free from contact with the quenching fluid so that after removal of the drum from the quenching fluid one portion of the drum will be extremely hard, while the other portion of the drum which has not been in contact with the quenching fluid will be extremely tough. f

hile various apparatuses may be provided for carrying out the method described above, I have found thatthis method may be conveniently and efficiently carried out on the apparatus disclosed in the accompanying drawings, wherein V Figure 1 is a central vertical sectional view through the apparatus,

Figure 2 is a fragmentary horizontal sectional view taken substantially on the plane indicated by the line 2-2 of Figure 1,

Figure 3 is an enlarged sectional view showing the details of construction of the means for preventing initial contact of the quenching fluid with the outer periphery of the brake drum and Figure 4 is a view similar to Figure 3 of a slightly modified form of apparatus.

Referring now particularly to the drawings wherein like reference characters designate corresponding parts throughout all views of the same 10 designates a supporting member which may be in the form of a spider and which supports the lower die, and expansible form hereinafter to be described.

Mounted on the supporting member 10, in a centrally arranged depression 11, is a lower or supporting die 12. The lower die 12 is provided with a plurality of radially arranged fluid passages 14, and a relatively deep annular groove 15 which is provided at its base with a plurality of spaced sockets 16 communicating with threaded apertures 17. The upper face of the lower die is provided with a relatively wide but shallow groove 18 to receive the fianges of the segments of the expanding form hereinafter to be described and is further provided with the inserts 13 and 13, which project above the upper face of the die to form bearing surfaces for the said segments.

Mounted on the inserts 13 and 13 is an expansible form composed of a plurality of segmental die or form members 19, each of which is provided with a flange 20 adapted to be received in the groove 18 formed in the lower die 12. As clearly illustrated in Figure 1 of the drawing, the flanges 2O are of less thickness than the width of the grooves 13, whereby radial movement of the form members 19 is permitted.

rlhe segmental die or form members 1.9 are adapted to be radially displaced by a pilot expander or ram 21, the latter being provided with a reduced extension 22 having a bearing in a bushing 23 carried by the supporting member 10. As clearly illustrated in Figure 1 of the drawing, the lower eX- tremity of the extension 22 is provided with a socket 24 in which is mounted a spring 25 having one end bearing against the base of the socket and its other end bearing against a plate 26 carried by the lower end of the bushing 23. As will be readily apparent, the spring 25 tends to urge the pilot expander or ram upwardly to permit inward radial movement of the segmental die members 19. To limit upward movement of the ram 21, there is provided abolt 27 threaded into the lower end of the extension 22. This bolt projects through the plate 26, being slidably received in an aperture arranged centrally of this plate and is adapted to receive at its lower extremity a threaded member or nut 28. It will be apparent that contact of the nut 28 with the plate 26 will limit upward movement of the ram 21.

For forcing the ram 21 downwardly against the tension of the spring 25, there is provided a piston 29, this piston being mounted for reciprocation in a suitable chamber 30 formed in an upper supporting member 31, which member may also be of a spider shape. For maintaining the piston expander 29 in alignment with the rain 21, there may be provided a centering pin or piston 32 which is carried by the upper supporting member and is adapted to be slidably received in a. socket 33 formed in the upper face of the ram 21. rlChe expander 29 may be actuated in any desired manner as by the admission of compressed air int-o the chamber 30 and the downward movement of the piston expander 29 forces the ram 21 downwardly against the tension of the spring 25 to expand the segmental form members 19. While it is immaterial what means may be provided for actuating the piston expander, it is essential that there be a definite relation between the force of the actuating means and the spring 25 so that the expansible form member 19 may be radially displaced only a predetermined desired amount. This is extremely important since the brake drum when located is of greater diameter than the ultimate diameter desired and is loosely mounted on the expansible form which has been previously adjusted to the desired inner diameter of the brake drum.

In Figure 1 of the drawing, I have shown a brake drum designated generally by the reference character 34. This brake drum is provided with the web portion 35, the lower flange 36, and may if desired be provided with the inclined portion 37 which extends between what might be termed the drum portion proper 38 of the brake drum and the web 35.

As clearly illustrated in Figure 1 of the drawings the brake drum 34 is adapted to loe-mounted on the segmental form members medalla r 19 each of which `is provided with a cut away portion V319,:which together form substantially a circumferential recess adapted to receive the web ofthe brake drinn. For clainping-fthe web cf the brake drum in the recess 39, there is rprovided an upper die which' is carried by the upper support 31 and which is adapted to engage the web 35 of the.

`form a plurality of fluid 'passages 43, which communicate at their lower ends with the iuid passages 14 foi-ined in the lower die 12 and which communicate at their upper end with diagonally extending passages 44 formed in the upper portion of the form members 19 between the passages 43 and the central chamber 42. It will thus be seen that there is provided a continuous fluid passage from below the lower die 12 past the form men'ibers 19, through the upper portions of the forin members 19 and out through the upper support 31.

ln operation, with the brake drum clamped on the apparatus as illustrated in Figure 1 of the drawing, the complete apparatus is lowered into a bath of quenching fluid preferably oil. By virtue of the spider' form of the lower support 10, the quenching fluid is permitted to flow upwardly through the fluid pas ges 14, 43 and 44 to the central chamber 'cin which it passes through the grooves 41 to the spider portion of the support 31, where it passes upwardly through the support 31, after which it may flow over the edges of said support and back down into the tank.

The size of the lower support 10 and lower die 12 is such that when the apparatus is lowered into the vat of oil` pressure is exerted on the surface of the oil or quenching fluid by the lower support and lower die. rifhus the quenching fluid is forced under pressure up through the passages aforesaid, in advance of the flow of the quenching fluid around the outer periphery of the lower die and form and therefore in advance of the contact of the quenching fluid with the outer periphery of the brake drum.

As brought out before, it is an object of this invention to assure contact of the quenching fluid with the interior of the brake drinn in advance of the contact of the quenching fluid with the outer periphery of the brake drum, and to accomplish this result there is provided a bearing or supporting ring on the lower *die 12. This bearing or supporting ring 45 is mounted in the annular groove 15 in the` lower die 12, being held in place by bolts :46,Y

which pass loosely throughthebearing ring` 45 and which engage in the spaced threaded apertures 17 formed-in the lower die. Surrounding the bolts 46 are springs 47, .which bearat one end against the base of the sockets 16 foi-ined in the lowerdie 12,'and which bearat their other ends against the base of sockets 48 formed in thel bearing ring 45.- It will thus be apparentthat the springs 46 tend to constantly urge -thebearing ring 45c z iq wardlyinto Contact witlrthebralie drum 34 mounted in thenappafratus. By virture of the yieldable mounting of the bearingring 435, this bearingqring willalways be firmly-pressed against the lower flange 36 of the brake druin i to ferm a tight seal againstthis lower flange. Further, `movement yof the bearing ring 45 will permit the apparatus to vbe used with brake drums -of different-heights, since the bearingl ring will immediately adapt itself to i the height of the brake drum.

For forming a further seal with'the lower edge of the brake drum V34, there is provided a guard 'ring'49 which is mounted vin a recess 50 i formed on the inner periphery of theA bearingvn ring 45 and which is secured to` the bearing ring by a pluralityv of spaced screws 51, This if guard ring is providedwith an upstanding flangeQ formed on -its inner periphery,

which flange may be curved to conform to the curve of the lower edge ofthe brake druin34.

From theV above, it will be obvious that the bearing ring 45 and guard ring491will form a tight seal between the flange 36 of the brake.

druni34 'and the lower die 12.- Thus quenching fluid forced upwardly through the fluid passage `14, is preventedfrom `passing to the outside of the brake-idruinand is forced upwardly through the passages'43 so as to'coni tact initially with the inner periphery of the bralredrum 34. Theinitial contact: of the quenching fluid with the inner periphery of of thebrake drum to entirely quench 'the Same.

1t is to be further noted thatiby virtue i of the fact that the web' 35 is clamped'between the upperA die 40 and the top ofthe form members 19,7this webnwill be substanf tially protected .from contact with the' quenching fluid so that this web will remain tough after the quenchingoperation.

For quenching drums which arenot pro-- vid'edffwith the lower flangefBG'I have pro vided the structure'illustrated in Figure'4 of` the drawing. In this viewy'it will bevnotedV that there isprovided the: guardfring45 which is mounted: in the vdie12 in a manner; i

similar =to the Vmounting of the bearingiring 45 in the die 12. In place, however, of the guard ring 49, there is provided a ring 53 which is mounted by means of a plurality of' spaced bolts 54 in the recess 55 formed in the bearing ring 45T The upper face of the guard ring` 53 is plane so as to form an intimate contact with the lower edge 56 of the brake drum 57. It will thus be seen that a tight seal will be formed between the lower edge of the brake drum 57 and the lower die l2 so that quenching fluid forced upwardly through the lower die 12 will be prevented from passing outwardly between this lower die 12 and the lower edge of the brake drum. From the above, it will be apparent that I have provided a method and apparatus whereby brake drums may be quenched by first contacting a quenching fluid with the inner periphery of the brake drum, while maintaining the outer periphery of the brake drum free from Contact with the quenching fluid and that subsequently the quenching fluid will be permitted to contact with the outer periphery of the brake drum to completely quench the brake drum. It will further be apparent that I have provided means which function not only to seal the lower edge of the brake drum, but also to permit the apparatus to be efliciently used on brake drums of varying heights, so that a single apparatus may be used for a number of diiA ferent types of brake drums.

While I have disclosed my invention as adapted particularly for the quenching of brake drums, it is to be understood that the description is for the purposes of illustration only and that the inventive principles may be embodied in apparatuses for quenching articles of any size or shape, or for treating articles of any size or shape with any character of a fluid. The particular embodiment disclosed therefore is not to be construed as definitive of the limits of my inventive idea, and I reserve the right to make such changes in the details of construction and arrangement of parts as will fall within the purview of the attached claims.

What I claim as my invention is:

l. The method of quenching a brake drum which consists in initially directing a quenching fluid into contact with one face of the heated drum while preventing contact of the quenching fluidr with the other face of the drum, and in subsequently permitting contact of the quenching fluid with the second mentioned tace of the drum.

2. Those steps in the method of hardening a brake drum which consists in initially directing a quenching fluid into contact with the inner periphery of the heated drum while preventing contact of the quenching fluid with the outer periphery of the drum and in subsequently ilowing the quenching iluid into contact with the outer periphery of the drum.

3. The method of quenching a brake drum 

